Eu -labeled IgG-based time-resolved fluoroimmunoassay for highly sensitive detection of aflatoxin B in feed.

Background: Aflatoxin B (AFB ) is a kind of toxic and carcinogenic mycotoxin. A time-resolved fluoroimmunoassay (TRFIA) was established for quantitative detection of AFB in feed using Eu -labeled IgG as tracer.

Results: Monoclonal antibody (McAb) against AFB (9B11-D7) was prepared through immunization and cell fusion and was identified as high affinity, specificity and sensibility by enzyme-linked immunosorbent assay (ELISA). The 50% inhibition value (IC ) was 0.81 ng mL , the limit of detection (LOD) was 0.10 ng mL and detection range was 0.10-3.94 ng mL . Goat anti-mouse immunoglobulin G (IgG) was modified by Eu -DATT, generating Eu -labeled IgG. Under optimal assay conditions, TRFIA was shown to be highly sensitive and specific in detection of AFB . The IC and LOD were 94.73 pg mL and 3.55 pg mL , respectively, and detection range was 3.55-1.11 × 10  pg mL . Cross-reactivity with AFM , AFB , AFG and AFG was 31.26%, 37.6%, 127.46% and 35.74%, respectively, but zero with other analogues. In determination of AFB spiked in feed sample, TRFIA showed high accuracy and precision. The average recoveries ranged from 93.71% to 97.80%, and coefficient of variation was 1.25-3.73%. Good correlation between TRFIA and HPLC was demonstrated for determination of AFB in feeds, confirming the reliability of the developed method.

Conclusion: The developed TRFIA exhibited good potential for employment in the ultrasensitive detection of AFB in feed and could be used to determine total aflatoxins. © 2017 Society of Chemical Industry.